An arrangement of the kind described above is disclosed in German published patent application DE-OS 31 06 315. This known arrangement is utilized for monitoring the circulatory system, measuring blood pressure and to permit self-monitoring by persons having circulatory diseases; however, it can also be used by persons who during work or when engaging in sport activity must remain under special supervision of a physician.
The requirement of monitoring vital functions is, however, not limited to the area of medicine; instead, it is also needed for persons who must perform rescue operations with breathing protection equipment such as fire-fighting personnel either in service or during practice sessions as well as rescue or deep sea divers or by workers who belong to a mine disaster rescue team.
Such activities under difficult conditions cause an extreme stress on the performance capability of the human body which is easily overestimated especially when persons have to be rescued under time pressure. In these situations there often is the danger that the limits of endurance is recognized too late during the rescue work and the rescue operation can become endangered in that the particular rescue worker becomes unavailable for the operation without this being monitored or otherwise noticed.
The known arrangement provides that an appropriate sensor be attached to the holders of a spectacle frame for monitoring vital functions. The sensor is pressed against the temple region of the wearer by the clamping pressure and this can be supported as needed by means of a band pulling the holders of the spectacle frame together.
It is a disadvantage of this known arrangement that a spectacle frame must be worn in each instance even when the particular person does not wear spectacles. In addition, such a spectacle frame unnecessarily hinders free movement when wearing a face mask. The required sealing is not assured when full masks are worn.
Furthermore, the contact between the surface of the skin and the sensor can be interrupted because of slippage by the formation of perspiration on the skin of the wearer during strenuous work activity.